Adenosine

INTRODUCTION

Indications

Conversion of paroxysmal supraventricular tachycardia (PSVT) to normal sinus rhythm when vagal maneuvers are unsuccessful. As a diagnostic agent (with noninvasive techniques) to assess myocardial perfusion defects occurring as a consequence of coronary artery disease.

Action

Restores normal sinus rhythm by interrupting reentrant pathways in the AV node. Slows conduction time through the AV node. Also produces coronary artery vasodilation. Therapeutic Effects: Restoration of normal sinus rhythm.

Adverse Reactions/Side Effects

CNS: apprehension, dizziness, headache, head pressure, light-headedness. EENT: blurred vision, throat tightness. Resp: shortness of breath, chest pressure, hyperventilation. CV: facial flushing, transient arrhythmias, chest pain, hypotension, palpitations. GI: metallic taste, nausea. Derm: burning sensation, sweating. MS: neck and back pain. Neuro: numbness, tingling. Misc: heaviness in arms, pressure sensation in groin.

PHYSICAL THERAPY IMPLICATIONS

Examination and Evaluation

• Assess heart rate, ECG, and heart sounds, especially during exercise (See Appendices G, H). Although intended to treat certain arrhythmias, this drug can precipitate new, transient arrhythmias (proarrhythmic effect). Report any rhythm disturbances or symptoms of increased arrhythmias, including palpitations, chest pain, shortness of breath, hyperventilation, fainting, and fatigue/weakness.

• Assess blood pressure periodically, and compare to normal values (See Appendix F). Report low blood pressure (hypotension), especially if patient experiences dizziness, light-headedness, or other symptoms.

• Assess any neck or back pain to rule out musculoskeletal pathology; that is, try to determine if pain is drug induced rather than caused by anatomic or biomechanical problems.

• Assess signs of parasthesia (numbness, tingling). Perform objective tests, including electroneuromyography and sensory testing to document any drug-related neuropathic changes.

• Assess dizziness that might affect gait, balance, and other functional activities (See Appendix C). Report balance problems and functional limitations to the physician and nursing staff, and caution the patient and family/caregivers to guard against falls and trauma.

Interventions

• Because of an increased risk of cardiac arrhythmias, use caution during aerobic exercise and endurance conditioning. Terminate exercise if patient exhibits untoward symptoms (chest pain, shortness of breath, etc.) or displays other criteria for exercise termination (See Appendix L).

Patient/Client-Related Instruction

• Remind patients to take medication as directed to control arrhythmias even if they are asymptomatic.

• Counsel patients about additional interventions to help control cardiac dysfunction, including regular exercise, weight loss, sodium restriction, stress reduction, moderation of alcohol consumption, and smoking cessation.

• Instruct patient or family/caregivers to report other troublesome side effects such as severe or prolonged headache, apprehension, blurred vision, facial flushing, throat tightness, skin reactions (increased sweating, burning sensation), or GI problems (nausea, metallic taste).

Pharmacokinetics

Absorption: Following ...